MzScheme and MrEd are now version 301.6 in the SVN repository trunk.
This version cleans up a few corners:
* JIT works in 3m.
* `call/ec' calls its argument as a tail call, and the body of
`let/ec' is in tail position with respect to the `let/ec' form.
* Added `struct-type-make-constructor' and `struct-type-make-predicate'.
Matthew